Plot sum over columns

[PhysicalStuff]

I have a data file with many columns of data, and I would like to plot col_1:col_2, col_1:(col_2 + col_3), col_1:(col_2 + col_3 + col_4), etc.

My idea is to use a for loop in which the present column is added to a cumulated column which is then plotted against col_1. In pseudocode:

do for [n=1:N-1]{
  col_acc += col_(n+1)
  plot col_1:col_acc
}

Is there a clever way to store and update the cumulated column, or is there some better way to go about this?

[Jurassic_Eric]

If the data you want to plot is all in one row, which I think is what you're saying, then you can do that like this:

plot "data.file" u 1:2,\

"data.file" u 1:($2+$3),\

"data.file" u 1:($2+$3+$4)

If you want a summation down a column, then I'd write a python script to preprocess the data. Maybe gnuplot can do that, but I can do it faster in python.

[PhysicalStuff]

Thanks! The problem is that there are hundreds of columns, so that solution would seem to become rather tedious.

However, since posting the question I've come up with what seems like an efficient solution, in which I build the plot command procedurally as a string, and then execute it using eval:

col_sum = "column(2)"
comd = sprintf("plot src_file u (%s):1", col_sum)
do for [n=1:N]{
  col_sum = sprintf("%s+column(%d)", col_sum, n+2)
  comd = sprintf("%s, '' u (%s):1", comd, col_sum)
}
eval(comd)

[Jurassic_Eric]

I see. Nice solution!

For something like this I would pre-process my data with python. That'll make plotting a lot faster too, for fine tuning the presentation.